GB1418867A - Gas-fired appliance - Google Patents

Abstract

1418867 Gas burners; air heating stoves; regulating combustion IMPERIAL METAL INDUSTRIES (KYNOCH) Ltd 6 Nov 1972 [25 Oct 1971 1 March 1972] 49448/71 and 9542/72 Headings F4S F4T and F4W A gas-fired appliance comprises a combustion chamber located over a gas burner, a further chamber for containing primary combustion air, an injector assembly comprising a burner mixing tube leading from the further chamber to the gas burner and means to inject gas into the burner mixing tube to entrain primary combustion air therewith, and a passage for air from the further chamber into the combustion chamber to provide a secondary air supply derived from the primary air supply. In the gasfired water heater of Fig. 1, a fan 15 draws fresh air along a tube 8 and through an opening 16, and forces the air into a primary air chamber 11. Gas emitted from a jet 13 mixes with air from the primary air chamber in a burner mixing tube 9. The mixture burns at the ports of a burner 3 and is mixed with secondary air supplied from the primary air chamber through an orifice 18. In the gas-fired water heater of Fig. 2 a fan forces air through an air intake 29 into a primary air chamber. Gas fed through a jet 31 mixes with primary air in a burner mixing tube 33 and burns in a burner 34. Air flows through apertures (30), Fig. 3 (not shown), in a bulkhead to a space 25 forming a secondary air chamber. Secondary air flows into a combustion chamber, defined by a casing 22, through an open bottom 26. The combustion chamber is provided with thermally insulated curved portions (39) which direct the combustion gases closely around a water-carrying tube (36) provided with helically extending fins. The appliance of Fig. 5 includes a radiant and convector gas fire 100 for heating a room and a gasfired water heater. Air from a main inlet duct 102 is pressurized in an inlet duct 110, forming a primary air chamber, by a fan 108. Gas from a jet 112 mixes with primary air in a burner mixing tube 111 and burns in burners 113. A secondary air chamber is supplied with air from the primary air chamber through orifices 114. Secondary air flows into the combustion chamber through an orifice 115. The flame impinges on radiants 116 visible through a glass door 117. Combustion gases pass through a heat exchanger 105 and leave through a main outlet duct 103 coaxial with the main inlet duct 102. Air bled through an orifice 118 passes over the heat exchanger 105 and leaves through a grill 119. The water heater 106 receives air from the inlet duct 110. Combustion gases leave through a duct 107 and pass into the main outlet duct 103. In a modified form, air leaving through the grill 119 is drawn in by a fan (151), Fig. 7 (not shown). A plurality of radiants each having a mixing tube supplying a burner may be provided. A valve in the form of a flap may be provided in the mixing tube. In any of the forms described the appliance may be provided with a fan in the flue outlet from the combustion chamber and with a pilot burner.